The only downside I see with more forums is less visibility. Most people don't seem to use the new posts button, but might regularly check general woodworking and miss the carving or veneering.
You make a good point about 'visibility', but I would argue that - speaking only for myself - I have specific interests, which for the moment are wood staining, power tool reviews, joinery, carving and veneering all listed in terms of importance at this point in time. Now, for instance, if Charles Neil did not have his own forum on this website I think he would not hear my plea for help if my staining query were buried in the General Woodworking forum and not in his specfic forum.
Secondly, I would also politely argue that, having the website well organized into realatively specific forums makes (1) finding information quicker and (2) enables posting your query in the correct forum much easier, if you look for the correct forum before beginning your thread, that is. I am guilty of just that. I have posted queries in General Woodworking only to come back later to discover that my thread had been moved to the forum I should have posted it in in the first place. My mistake for not seeking out the correct forum to post in. That could be a woodworking sickness medically referred to as general woodworkingitis.
And lastly, I think we have all vistied forums and popped open the General Woodworking forum only to find questions ranging from A to Z. I find that very disheartening and confusing. I've blabbed on and must say that none of what I have said directly resolves your 'visibility' concern. However, recently, after you posted to a thread I began, I jumped over to the Game Call Making forum (my first visit to that forum) then to your own website, which opened my eyes to game calling. In that sense, this made game call making more visible to me than it was before you posted to my thread. I think there are many ways that 'visibility' can come about on a website.
I think WoodBarter is one of the most organized forums on the web. That said, with or without a carving and veneering forum it still rocks.
Thanks!